vendredi 25 novembre 2016

One of the biggest puzzles in physics is that eighty-five percent of the matter in our universe is “dark”: it does not interact with the photons of the conventional electromagnetic force and is therefore invisible to our eyes and telescopes. Although the composition and origin of dark matter are a mystery, we know it exists because astronomers observe its gravitational pull on ordinary visible matter such as stars and galaxies.

Some theories suggest that, in addition to gravity, dark matter particles could interact with visible matter through a new force, which has so far escaped detection. Just as the electromagnetic force is carried by the photon, this dark force is thought to be transmitted by a particle called “dark” photon which is predicted to act as a mediator between visible and dark matter.

“To use a metaphor, an otherwise impossible dialogue between two people not speaking the same language (visible and dark matter) can be enabled by a mediator (the dark photon), who understands one language and speaks the other one,” explains Sergei Gninenko, spokesperson for the NA64 collaboration.

CERN’s NA64 experiment looks for signatures of this visible-dark interaction using a simple but powerful physics concept: the conservation of energy. A beam of electrons, whose initial energy is known very precisely, is aimed at a detector. Interactions between incoming electrons and atomic nuclei in the detector produce visible photons. The energy of these photons is measured and it should be equivalent to that of the electrons. However, if the dark photons exist, they will escape the detector and carry away a large fraction of the initial electron energy.

Therefore, the signature of the dark photon is an event registered in the detector with a large amount of “missing energy” that cannot be attributed to a process involving only ordinary particles, thus providing a strong hint of the dark photon’s existence.

If confirmed, the existence of the dark photon would represent a breakthrough in our understanding the longstanding dark matter mystery.

The name’s TIM, Robot TIM – meet the spy patrolling the 27-km tunnel of the Large Hadron Collider (LHC). TIM, the Train Inspection Monorail, is a mini vehicle transporting a set of instruments along tracks suspended from the tunnel’s ceiling. This smart machine is used for real-time monitoring of the LHC tunnel: the tunnel structure, the oxygen percentage, the communication bandwidth and the temperature.

Image above: TIM uses the tracks of the former Large Electron Positron (LEP) monorail. This image from 1991 shows the LEP monorail, which carried materials and workers when the tunnel housed the LEP collider. LEP was closed down in 2000 to make way for the construction of the LHC in the same tunnel. (Image: Patrice Loiez/CERN).

TIM provides visual and infrared imaging of the LHC tunnel and can move up to 6 km/h. It can also pull small wagons for specific tasks.

Two TIM units are currently running in the LHC tunnel, parked in a service tunnel of one of the LHC experiment, waiting for commands.

Note:CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

The Sentinel-1 satellites have shown that the Millennium Tower skyscraper in the centre of San Francisco is sinking by a few centimetres a year. Studying the city is helping scientists to improve the monitoring of urban ground movements, particularly for subsidence hotspots in Europe.

Completed in 2009, the 58-storey Millennium Tower has recently been showing signs of sinking and tilting. Although the cause has not been pinpointed, it is believed that the movements are connected to the supporting piles not firmly resting on bedrock.

Millennium Tower sinking

To probe these subtle shifts, scientists combined multiple radar scans from the Copernicus Sentinel-1 twin satellites of the same area to detect subtle surface changes – down to millimetres. The technique works well with buildings because they better reflect the radar beam.

It is also useful for pinpointing displacement hotspots over large areas, thanks to Sentinel-1’s broad coverage and frequent visits.

San Francisco displacement

Working with ESA, the team from Norut, PPO.labs and Geological Survey of Norway have also mapped other areas in the wider San Francisco Bay Area that are moving. These include buildings along the earthquake-prone Hayward Fault, as well as subsidence of the newly reclaimed land in the San Rafael Bay.

An uplift of the land was detected around the city of Pleasanton, possibly from the replenishment of groundwater following a four-year drought that ended in 2015.

European cities experience similar subsidence, and the San Francisco study is helping because it contains a multitude of features.

Bay Area displacement

For example, the area around Oslo’s train station in Norway is reclaimed land. Newer buildings, such as the nearby opera house, have proper foundation into bedrock, but the older parts of the station experience severe subsidence.

“Experience and knowledge gained within the ESA’s Scientific Exploitation of Operational Missions programme give us strong confidence that Sentinel-1 will be a highly versatile and reliable platform for operational deformation monitoring in Norway, and worldwide,” noted John Dehls from the Geological Survey of Norway.

The studies of San Francisco and Oslo are paving the way for moving from targeted case studies to a nationwide or even continental-scale land deformation service.

“The Copernicus Sentinel-1 mission is, for the first time, making it possible to launch operational national deformation mapping services,” said Dag Anders Moldestad from the Norwegian Space Centre.

The open data policy and regular coverage plan of Copernicus promise cost-efficient and reliable services.

Oslo train station on the move

“In Norway, we have already initiated a framework project to provide nationwide basic deformation products to the public, with a free and open data policy. Many other countries in Europe are also working towards setting up similar services,” noted Dr Moldestad.

The Sentinel-1 twins provide ‘radar vision’ for Europe’s Copernicus environment monitoring programme. In addition to watching land movements, they feed numerous other services for monitoring Arctic sea ice, routine sea-ice mapping, surveillance of the marine environment, mapping for forest, water and soil management, and mapping to support humanitarian aid and crisis situations.

mercredi 23 novembre 2016

The European Data Relay System began servicing Europe’s Earth observing Copernicus programme yesterday, transferring observations in quasi-real time using cutting-edge laser technology.

The EDRS–SpaceDataHighway will now begin providing a commercial service to the European Commission’s Copernicus Sentinels – the first and only of its kind. EDRS is a public–private partnership between ESA and Airbus Defence and Space, with ESA supporting the initial technology development and the company providing the commercial service. The European Commission is EDRS’s anchor customer through its Sentinel-1 and -2 missions.

EDRS-A

EDRS accelerates the transmission of data from low-orbiting satellites like the Sentinels to the end user on the ground. It does so by locking onto the satellites with a laser beam as they pass below, and immediately relaying the information to European ground stations via a high-speed radio beam.

Low-orbiting satellites must usually wait until they travel within view of a ground station to downlink the data they have gathered, resulting in a delay of up to 90 minutes per 100-minute orbit. This is because most ground stations that serve low-orbiting satellites are located in the polar regions, although the Sentinels have additional stations in Italy and Spain.

Nevertheless, Earth observation satellite data are increasingly being used for time-sensitive applications like disaster response, maritime surveillance and security, where speed is of the essence.

EDRS will help to solve this problem. As the world’s first optical satellite communication network in ‘geostationary’ orbit – where satellites takes 24hr to circle Earth and thus appear to ‘hang’ in the sky – it will relay unprecedented amounts of potentially life-saving data per day in near-real time.

Space data without delay

The EDRS-A first node will now start collecting data from Sentinel-1A. The two satellites will link via laser beam up to 15 times per day.

The EDRS-C second node will be launched in 2017 to help transfer the massive amounts of data being sent back and forth over Europe.

Unlike EDRS-A, which is hosted on a Eutelsat commercial satellite, EDRS-C is a dedicated satellite built specifically for the system.

Both nodes carry a TESAT payload with a laser intersatellite terminal developed under funding by the DLR German Aerospace Center. EDRS-A also carries a high-speed Ka-band intersatellite payload to relay data to and from the International Space Station.

The first two satellites are planned to be complemented by the EDRS-D third node over Asia in 2020.

EDRS-D is part of a programme called GlobeNet, which will extend the EDRS quasi-realtime data relay coverage from Europe to worldwide.

GlobeNet

GlobeNet will also link to both manned and remotely piloted aircraft, providing two-way communications that can be used for command, control and the rapid download of sensor data, complementing those obtained from Earth observation satellites.

The net result will be that Earth observation data can be received anywhere on Earth in near-real time, greatly increasing its value for a host of time-critical applications such as disaster and emergency response.

“As the first commercial data relay service in the world to use lasers, the EDRS–SpaceDataHighway represents forward-thinking innovation at its best. ESA will continue working with our partners, Airbus Defence and Space and the European Commission, to keep pushing the envelope of technological progress by extending this success to worldwide coverage with GlobeNet,” said Magali Vaissiere, ESA’s Director of Telecommunications and Integrated Applications.

“The EDRS–SpaceDataHighway offers a new dimension of data access from our Sentinel satellites, allowing faster access to images as well as a back-up capacity to classical ground receiving stations. This becomes increasingly important to satisfy the increasing demands of our user communities,” says Josef Aschbacher, ESA’s Director of Earth Observation Programmes.

“SpaceDataHighway is no longer science fiction, it will revolutionise satellite communications,” added Evert Dudok, Head of Communications, Intelligence & Security at Airbus Defence and Space.

“It will totally change the way humanitarian crisis, maritime safety and the protection of environment can be managed.”

“Germany has strategically invested in optical communication and intends to continue with the evolution in the ESA ‘ScyLight’ programme. Now we have chance to transform the European technological leadership into a market leadership,” said Dr Gerd Gruppe of DLR’s Executive Board, responsible for space administration.

Fire safety is a crucial component of space living. As we partner with industry and international space agencies to develop deep space habitation capabilities, we are leveraging every opportunity to validate important habitation-related systems and operations in low-Earth orbit. The second Spacecraft Fire Safety experiment, or Saffire-II, is a fire experiment with nine material swatches that will be ignited in a cargo ship as it orbits Earth. Saffire-II is the second in a series of three fire safety experiments, and builds on the data captured during Saffire-I with an expanded test portfolio of new materials.

Cygnus Spacecraft Departs ISS (archive image). Image Credit: NASA

Saffire-II launched on OA-5 in October 2016. The nine samples in the experiment kit aboard the Cygnus cargo vehicle include a cotton-fiberglass blend, Nomex, and the same acrylic glass that is used for spacecraft windows. After the spacecraft departs the station, and before its destructive reentry to Earth, mission controllers on the ground will remotely ignite the samples.

Saffire-II mission updates will be added below as data and imagery are returned from the orbiting Cygnus vehicle.

Tuesday, Nov. 22, 2106

6:00 p.m: The Saffire team has successfully downlinked images from the nine samples tested in Saffire-II. The first sample has a thin sheet of poly(methyl methacrylate) (PMMA), also known as plexiglass, that is being used to ignite Nomex, a commercially available, flame-resistant material that is used on spacecraft for cargo storage bags and as a fire barrier. The second sample is a plexiglass sheet (5 cm wide x 29 cm long x 10 cm wide), a material that is used for spacecraft windows. The Saffire investigators will continue to downlink data and images on Tuesday and Wednesday nights and provide additional updates as they are available.

Saffire-II Sample 7

Monday, Nov. 21, 2016

9:30 p.m.: All nine samples have burned and preliminary telemetry indicate that data and images were recorded as expected for all 9 samples and flow visualization. The Saffire-II hardware performed very well and there were no issues. The team will spend tonight downlinking the sensor and image data and begin analysis of the dataset tomorrow morning. Updates on Tuesday will include preliminary sensor data and images from the burns.

Saffire-II Sample 9

8:04 p.m.: Samples 1-6 have been ignited and we’ve captured more than 106,000 images. Samples 1-4 were a silicon material at different thicknesses. Samples 5 and 6 were the same cotton-fiberglass blend that was burned on Saffire-I; one was at the same flow speed as Saffire-I and the other was at the flow speed planned for Saffire-III. Samples 7-9 up next! The images will be downlinked to Orbital ATK overnight and transferred to researchers at NASA-GRC for analysis tomorrow. Initial images will be released as they are available.

7:14 p.m.: We've received confirmation that the first Saffire-II test sample has been ignited.

6:04 p.m.: Orbital ATK has confirmed that the Saffire-II experiment is powered and we are receiving telemetry. We remain on track for a 7:00 p.m. sample ignition.

8:22 a.m.: Shane Kimbrough of NASA and Thomas Pesquet of the European Space Agency commanded the International Space Station’s Candadarm2 robotic arm to release the Cygnus spacecraft.

mardi 22 novembre 2016

The boeing 747 which transported the solar aircraft arrived from Abu Dhabi

Solar Impulse 2 is back in Dübendorf (ZH) after completing its world tour.

The pilots Bertrand Piccard and André Borschberg witnessed the landing of the cargo plane at the military airfield in Dübendorf. Dozens of aviation enthusiasts also attended.

Image above: Pilots Bertrand Piccard and André Borschberg witnessed the landing of the cargo plane at the military airfield in Dübendorf.

In front of the media and the public, the two drivers expressed their joy at seeing Solar Impulse 2 in Dübendorf. "For thirteen years we have lived only for Solar Impulse," summarized Bertrand Piccard. "For two years, it was our baby, our house, our friend and our tool," he added. The adventure is now over, but the project continues.

The solar plane was transported disassembled and stored in crates

SI2 stays in Dübendorf

The aircraft will be maintained, even if the flight costs are high, explained André Borschberg. The aircraft was designed to fly 2000 hours. There remains 1300. It would also be possible to exhibit it in a museum, but for now, it remains in Dübendorf (Switzerland).

Video above: Now in its final year of operations, on Nov. 30, 2016, NASA’s Cassini mission will begin a daring set of ring-grazing orbits, skimming past the outside edge of Saturn's main rings. Cassini will fly closer to Saturn’s rings than it has since its 2004 arrival. It will begin the closest study of the rings and offer unprecedented views of moons that orbit near them. Even more dramatic orbits ahead will bring Cassini closer to Saturn than any spacecraft has dared to go before.

First Phase in Dramatic Endgame for Long-Lived Cassini Spacecraft

A thrilling ride is about to begin for NASA's Cassini spacecraft. Engineers have been pumping up the spacecraft's orbit around Saturn this year to increase its tilt with respect to the planet's equator and rings. And on Nov. 30, following a gravitational nudge from Saturn's moon Titan, Cassini will enter the first phase of the mission's dramatic endgame.

Launched in 1997, Cassini has been touring the Saturn system since arriving there in 2004 for an up-close study of the planet, its rings and moons. During its journey, Cassini has made numerous dramatic discoveries, including a global ocean within Enceladus and liquid methane seas on Titan.

Between Nov. 30 and April 22, Cassini will circle high over and under the poles of Saturn, diving every seven days -- a total of 20 times -- through the unexplored region at the outer edge of the main rings.

"We're calling this phase of the mission Cassini's Ring-Grazing Orbits, because we'll be skimming past the outer edge of the rings," said Linda Spilker, Cassini project scientist at NASA's Jet Propulsion Laboratory, Pasadena, California. "In addition, we have two instruments that can sample particles and gases as we cross the ringplane, so in a sense Cassini is also 'grazing' on the rings."

On many of these passes, Cassini's instruments will attempt to directly sample ring particles and molecules of faint gases that are found close to the rings. During the first two orbits, the spacecraft will pass directly through an extremely faint ring produced by tiny meteors striking the two small moons Janus and Epimetheus. Ring crossings in March and April will send the spacecraft through the dusty outer reaches of the F ring.

"Even though we're flying closer to the F ring than we ever have, we'll still be more than 4,850 miles (7,800 kilometers) distant. There’s very little concern over dust hazard at that range," said Earl Maize, Cassini project manager at JPL.

The F ring marks the outer boundary of the main ring system; Saturn has several other, much fainter rings that lie farther from the planet. The F ring is complex and constantly changing: Cassini images have shown structures like bright streamers, wispy filaments and dark channels that appear and develop over mere hours. The ring is also quite narrow -- only about 500 miles (800 kilometers) wide. At its core is a denser region about 30 miles (50 kilometers) wide.

So Many Sights to See

Animation above: Saturn's rings were named alphabetically in the order they were discovered. The narrow F ring marks the outer boundary of the main ring system. Image Credits: NASA/JPL-Caltech/Space Science Institute.

Cassini's ring-grazing orbits offer unprecedented opportunities to observe the menagerie of small moons that orbit in or near the edges of the rings, including best-ever looks at the moons Pandora, Atlas, Pan and Daphnis.

Grazing the edges of the rings also will provide some of the closest-ever studies of the outer portions of Saturn's main rings (the A, B and F rings). Some of Cassini's views will have a level of detail not seen since the spacecraft glided just above them during its arrival in 2004. The mission will begin imaging the rings in December along their entire width, resolving details smaller than 0.6 mile (1 kilometer) per pixel and building up Cassini's highest-quality complete scan of the rings' intricate structure.

The mission will continue investigating small-scale features in the A ring called "propellers," which reveal the presence of unseen moonlets. Because of their airplane propeller-like shapes, scientists have given some of the more persistent features informal names inspired by famous aviators, including "Earhart." Observing propellers at high resolution will likely reveal new details about their origin and structure.

And in March, while coasting through Saturn's shadow, Cassini will observe the rings backlit by the sun, in the hope of catching clouds of dust ejected by meteor impacts.

Preparing for the Finale

During these orbits, Cassini will pass as close as about 56,000 miles (90,000 kilometers) above Saturn's cloud tops. But even with all their exciting science, these orbits are merely a prelude to the planet-grazing passes that lie ahead. In April 2017, the spacecraft will begin its Grand Finale phase.

After nearly 20 years in space, the mission is drawing near its end because the spacecraft is running low on fuel. The Cassini team carefully designed the finale to conduct an extraordinary science investigation before sending the spacecraft into Saturn to protect its potentially habitable moons.

During its grand finale, Cassini will pass as close as 1,012 miles (1,628 kilometers) above the clouds as it dives repeatedly through the narrow gap between Saturn and its rings, before making its mission-ending plunge into the planet’s atmosphere on Sept. 15. But before the spacecraft can leap over the rings to begin its finale, some preparatory work remains.

To begin with, Cassini is scheduled to perform a brief burn of its main engine during the first super-close approach to the rings on Dec. 4. This maneuver is important for fine-tuning the orbit and setting the correct course to enable the remainder of the mission.

Cassini spacecraft. Image Credits: NASA/JPL-Caltech

"This will be the 183rd and last currently planned firing of our main engine. Although we could still decide to use the engine again, the plan is to complete the remaining maneuvers using thrusters," said Maize.

To further prepare, Cassini will observe Saturn's atmosphere during the ring-grazing phase of the mission to more precisely determine how far it extends above the planet. Scientists have observed Saturn's outermost atmosphere to expand and contract slightly with the seasons since Cassini's arrival. Given this variability, the forthcoming data will be important for helping mission engineers determine how close they can safely fly the spacecraft.

Image above: China's first data relay satellite Tianlian-I is launched on a Long March-3C carrier rocket from the Xichang Satellite Launch Center.

China orbited its fourth tracking and data relay satellite in the Tianlian-1 range known as ‘Sky Link’ on Tuesday. The launch took place at 15:30 UTC from the Xichang Satellite Launch Center in Sichuan Province, utilizing a Long March 3C/G2 rocket.

China's Tianlian I-04 satellite launched by Long March 3C

The Chinese tracking and data relay satellites were developed by the China Academy of Space Technology (CAST) and it is similar to the American Tracking and Data Relay Satellite System (TDRSS) in concept.

The system is designed to support near-real-time communications between
orbiting spacecraft and ground control. The system will complement the
ground-based space tracking and telemetry stations and ships to support
future space projects.

Tianlian-1 data relay satellite

Like its predecessors, the Tianlian-1 (4) satellite is based on the DFH-3 bus. The DFH-3 (Dongfanghong-3) platform is a medium-capacity telecommunications satellite platform designed and developed by CAST.

Image above: This vertically exaggerated view shows scalloped depressions in a part of Mars where such textures prompted researchers to check for buried ice, using ground-penetrating radar aboard NASA's Mars Reconnaissance Orbiter. They found about as much frozen water as the volume of Lake Superior. Image Credits: NASA/JPL-Caltech/Univ. of Arizona.

Frozen beneath a region of cracked and pitted plains on Mars lies about as much water as what's in Lake Superior, largest of the Great Lakes, researchers using NASA's Mars Reconnaissance Orbiter have determined.

Scientists examined part of Mars' Utopia Planitia region, in the mid-northern latitudes, with the orbiter's ground-penetrating Shallow Radar (SHARAD) instrument. Analyses of data from more than 600 overhead passes with the onboard radar instrument reveal a deposit more extensive in area than the state of New Mexico. The deposit ranges in thickness from about 260 feet (80 meters) to about 560 feet (170 meters), with a composition that's 50 to 85 percent water ice, mixed with dust or larger rocky particles.

Images above: These two images show Shallow Radar (SHARAD) instrument data from two tracks in a part of Mars' Utopia Planitia region where the orbiting, ground-penetrating radar on NASA's Mars Reconnaissance Orbiter detected subsurface deposits rich in water ice. Images Credits: NASA/JPL-Caltech/Univ. of Rome/ASI/PSI.

At the latitude of this deposit -- about halfway from the equator to the pole -- water ice cannot persist on the surface of Mars today. It sublimes into water vapor in the planet's thin, dry atmosphere. The Utopia deposit is shielded from the atmosphere by a soil covering estimated to be about 3 to 33 feet (1 to 10 meters) thick.

"This deposit probably formed as snowfall accumulating into an ice sheet mixed with dust during a period in Mars history when the planet's axis was more tilted than it is today," said Cassie Stuurman of the Institute for Geophysics at the University of Texas, Austin. She is the lead author of a report in the journal Geophysical Research Letters.

Mars today, with an axial tilt of 25 degrees, accumulates large amounts of water ice at the poles. In cycles lasting about 120,000 years, the tilt varies to nearly twice that much, heating the poles and driving ice to middle latitudes. Climate modeling and previous findings of buried, mid-latitude ice indicate that frozen water accumulates away from the poles during high-tilt periods.

Martian Water as a Future Resource

The name Utopia Planitia translates loosely as the "plains of paradise." The newly surveyed ice deposit spans latitudes from 39 to 49 degrees within the plains. It represents less than one percent of all known water ice on Mars, but it more than doubles the volume of thick, buried ice sheets known in the northern plains. Ice deposits close to the surface are being considered as a resource for astronauts.

Image above: Diagonal striping on this map of a portion of Mars' Utopia Planitia region indicates the area where a large subsurface deposit rich in water ice was assessed using the Shallow Radar (SHARAD) instrument on NASA's Mars Reconnaissance Orbiter. The deposit holds about as much water as Lake Superior. Image Credits: NASA/JPL-Caltech/Univ. of Rome/ASI/PSI.

"This deposit is probably more accessible than most water ice on Mars, because it is at a relatively low latitude and it lies in a flat, smooth area where landing a spacecraft would be easier than at some of the other areas with buried ice," said Jack Holt of the University of Texas, a co-author of the Utopia paper who is a SHARAD co-investigator and has previously used radar to study Martian ice in buried glaciers and the polar caps.

The Utopian water is all frozen now. If there were a melted layer -- which would be significant for the possibility of life on Mars -- it would have been evident in the radar scans. However, some melting can't be ruled out during different climate conditions when the planet's axis was more tilted. "Where water ice has been around for a long time, we just don't know whether there could have been enough liquid water at some point for supporting microbial life," Holt said.

Utopia Planitia is a basin with a diameter of about 2,050 miles (3,300 kilometers), resulting from a major impact early in Mars' history and subsequently filled. NASA sent the Viking 2 Lander to a site near the center of Utopia in 1976. The portion examined by Stuurman and colleagues lies southwest of that long-silent lander.

Use of the Italian-built SHARAD instrument for examining part of Utopia Planitia was prompted by Gordon Osinski at Western University in Ontario, Canada, a co-author of the study. For many years, he and other researchers have been intrigued by ground-surface patterns there such as polygonal cracking and rimless pits called scalloped depressions -- "like someone took an ice-cream scoop to the ground," said Stuurman, who started this project while a student at Western.

Clue from Canada

In the Canadian Arctic, similar landforms are indicative of ground ice, Osinski noted, "but there was an outstanding question as to whether any ice was still present at the Martian Utopia or whether it had been lost over the millions of years since the formation of these polygons and depressions."

The large volume of ice detected with SHARAD advances understanding about Mars' history and identifies a possible resource for future use.

"It's important to expand what we know about the distribution and quantity of Martian water," said Mars Reconnaissance Orbiter Deputy Project Scientist Leslie Tamppari, of NASA's Jet Propulsion Laboratory, Pasadena, California. "We know early Mars had enough liquid water on the surface for rivers and lakes. Where did it go? Much of it left the planet from the top of the atmosphere. Other missions have been examining that process. But there's also a large quantity that is now underground ice, and we want to keep learning more about that."

Joe Levy of the University of Texas, a co-author of the new study, said, "The ice deposits in Utopia Planitia aren’t just an exploration resource, they’re also one of the most accessible climate change records on Mars. We don’t understand fully why ice has built up in some areas of the Martian surface and not in others. Sampling and using this ice with a future mission could help keep astronauts alive, while also helping them unlock the secrets of Martian ice ages.”

Mars Reconnaissance Orbiter (MRO). Imge Credits: NASA/JPL-Caltech

SHARAD is one of six science instruments on the Mars Reconnaissance Orbiter, which began its prime science phase 10 years ago this month. The mission's longevity is enabling studies of features and active processes all around Mars, from subsurface to upper atmosphere. The Italian Space Agency provided the SHARAD instrument and Sapienza University of Rome leads its operations. The Planetary Science Institute, based in Tucson, Arizona, leads U.S. involvement in SHARAD. JPL, a division of Caltech in Pasadena, manages the orbiter mission for NASA's Science Mission Directorate in Washington. Lockheed Martin Space Systems of Denver built the spacecraft and supports its operations.

(Highlights: Week of Nov. 14, 2016) - As the crew of the International Space Station prepared for the arrival of Expedition 50 crewmembers NASA astronaut Peggy Whitson, Russian cosmonaut Oleg Novitskiy of Roscosmos, and ESA astronaut Thomas Pesquet, who launched on Nov. 17, research continued on a variety of investigations including looking for meteors by turning away from deep space and watching the skies below the station.

NASA astronaut Shane Kimbrough inserted a fresh hard drive to record new images for the Meteor Composition Determination (Meteor) investigation making space-based observations of the chemical composition of meteors. The investigation captures high-resolution video and photographs of space rocks falling through Earth’s atmosphere using a software program to search for bright spots, which can later be analyzed on the ground. Measurements made by a spectrograph help determine a meteor's chemical makeup.

Image above: The moon, or supermoon, rises behind the Soyuz rocket at the Baikonur Cosmodrome launch pad in Kazakhstan Nov. 14. NASA astronaut Peggy Whitson, Russian cosmonaut Oleg Novitskiy of Roscosmos and ESA astronaut Thomas Pesquet launched on the rocket three days later for a six-month mission on the International Space Station. A supermoon occurs when the moon’s orbit is closest (perigee) to Earth. Image Credits: NASA/Bill Ingalls.

Meteors are relatively rare, and are difficult to monitor from the ground because of the interference created by Earth’s atmosphere. Investigating the elemental composition of meteors is important to our understanding of how planets developed. Continuous measurement of meteors and their interaction with Earth's atmosphere could help spot previously undetected or unnoticed meteors as they descend toward the ground. The investigation is installed in the station's Window Observational Research Facility (WORF).

Kimbrough installed a new facility on the space station that cuts back on crew involvement with autonomous payloads, giving them more time to spend on more complex investigations. The NanoRacks Black Box or Science Box is a footlocker-sized box designed to host a number of experiments with practically no monitoring from the crew. The box is installed in the Japanese Experiment Module (JEM) and, after connection to the appropriate cables, ground teams took over, commanding their investigations as needed and watching them through a video feed. These scientists confirmed the investigations currently installed in the Science Box were working as expected.

Image above: NASA astronaut Shane Kimbrough is seen inside the Cygnus cargo vehicle while it is docked to the International Space Station. Cygnus delivered approximately 5,000 pounds of science investigations, food and supplies to the orbiting laboratory. Image Credit: NASA.

Kimbrough took time to perform a unique outreach activity, sharing the book “I, Humanity” by Jeffrey Bennett as part of the Story Time From Space program -- an outreach effort combining literacy with science demonstrations recorded in orbit. Crew members read science, technology-, engineering- and mathematics- (STEM-) related children's books, and complete simple science concept experiments. Kimbrough discussed the subject of the book while on camera, and demonstrated the principles involved. Video and data collected during the demonstrations are downlinked and posted to a video library with accompanying educational materials.

The Story Time program is intended to inspire a new generation of schoolchildren to become interested in the STEM fields. The curriculum may help educators improve student understanding and interest in these subjects, preparing the next generation to pursue space-related careers.

Expedition 50 Suits Up and Launches

Video above: Expedition 50 crew members suited up and lifted off on their two-day journey to the International Space Station where they docked Nov. 19, officially starting their six-month mission on the orbiting complex Video Credit: NASA.

Crew members also conducted human research investigations this week, including Fine Motor Skills, Dose Tracker and Space Headaches.

Progress also was made on other investigations and facilities this week, including Veg-03, ISS Ham, ACE-T-1, EML Batch 1, Radi-N2, and the Fluid Science Laboratory.

Spiral galaxy NGC 3274 is a relatively faint galaxy located over 20 million light-years away in the constellation of Leo (The Lion). This NASA/ESA Hubble Space Telescope image comes courtesy of Hubble's Wide Field Camera 3 (WFC3), whose multi-color vision allows astronomers to study a wide range of targets, from nearby star formation to galaxies in the most remote regions of the cosmos.

This image combines observations gathered in five different filters, bringing together ultraviolet, visible and infrared light to show off NGC 3274 in all its glory. NGC 3274 was discovered by Wilhelm Herschel in 1783. The galaxy PGC 213714 is also visible on the upper right of the frame, located much farther away from Earth.

lundi 21 novembre 2016

Image above: A small cloud of dust and gas containing a new star being formed about 20,000 light years from Earth. Image Credits: X-ray: NASA/CXC/SAO/M.McCollough et al, Radio: ASIAA/SAO/SMA.

A snapshot of the stellar life cycle has been captured in a new portrait from NASA’s Chandra X-ray Observatory and the Smithsonian’s Submillimeter Array (SMA). A cloud that is giving birth to stars has been observed to reflect X-rays from Cygnus X-3, a source of X-rays produced by a system where a massive star is slowly being eaten by its companion black hole or neutron star. This discovery provides a new way to study how stars form.

In 2003, astronomers used Chandra’s high-resolution X-ray vision to find a mysterious source of X-ray emission located very close to Cygnus X-3. The separation of these two sources on the sky is equivalent to the width of a penny at a distance of 830 feet away. In 2013, astronomers reported that the new source is a cloud of gas and dust.

In astronomical terms, this cloud is rather small – about 0.7 light years in diameter. Astronomers realized that this cloud was acting as a mirror, reflecting some of the X-rays generated by Cygnus X-3 towards Earth.

“We nicknamed this object the ‘Little Friend’ because it is a faint source of X-rays next to a very bright source that showed similar X-ray variations,” said Michael McCollough of the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Massachusetts, who led the most recent study of this system.

The Chandra observations reported in 2013 suggested that the Little Friend had a mass between two and 24 times that of the Sun. This suggested that the cloud was a “Bok globule,” a small dense cloud where infant stars can be born. However, more evidence was needed.

To determine the nature of the Little Friend, astronomers used the SMA, a series of eight radio dishes atop Mauna Kea in Hawaii. The SMA found molecules of carbon monoxide, an important clue that the Little Friend is indeed a Bok globule. Also, the SMA data reveals the presence of a jet or outflow within the Little Friend, an indication that a star has started to form inside.

Image above: Cygnus X-3 is an X-ray binary where a compact source is pulling material away from a massive companion star. Chandra's high-resolution X-ray vision revealed a cloud of gas and dust that is a separated by a very small distance from Cygnus X-3. This gas cloud, dubbed the "Little Friend," is a Bok globule, the first ever detected in X-rays and the most distant one ever discovered. Astronomers detected jets produced by the "Little Friend", showing that a star is forming inside it. Image Credits: X-ray: NASA/CXC/SAO/M.McCollough et al, Radio: ASIAA/SAO/SMA.

“Typically, astronomers study Bok globules by looking at the visible light they block or the radio emission they produce,” said co-author Lia Corrales of the Massachusetts Institute of Technology in Cambridge, Mass. “With the Little Friend, we can examine this interstellar cocoon in a new way using X-rays – the first time we have ever been able to do this with a Bok globule.”

At an estimated distance of almost 20,000 light years from Earth, the Little Friend is also the most distant Bok globule yet seen.

The properties of Cygnus X-3 and its proximity to the Little Friend also give an opportunity to make a precise distance measurement – something that is often very difficult in astronomy. Since the early 1970s, astronomers have observed a regular 4.8-hour variation in the X-rays from Cygnus X-3. The Little Friend, acting as an X-ray mirror, shows the same variation, but slightly delayed because the path the reflected X-rays take is longer than a straight line from Cygnus X-3 to Earth.

By measuring the delay time in the periodic variation between Cygnus X-3 and the Little Friend, astronomers were able to calculate the distance from Earth to Cygnus X-3 of about 24,000 light years.

Chandra X-ray Observatory. Image Credits: NASA/CXC

Because Cygnus X-3 contains a massive, short-lived star, scientists think it must have originated in a region of the Galaxy where stars are still likely to be forming. These regions are only found in the Milky Way’s spiral arms. However, Cygnus X-3 is located outside any of the Milky Way’s spiral arms.

“In some ways it’s a surprise that we find Cygnus X-3 where we do,” said co-author Michael Dunham of CfA and the State University of New York at Fredonia. “We realized something rather unusual needed to happen during its early years to send it on a wild ride.”

The researchers suggest that the supernova explosion that formed either the black hole or neutron star in Cygnus X-3 kicked the binary system away from its original birthplace. Assuming that Cygnus X-3 and the Little Friend formed near each other, they estimate that Cygnus X-3 must have been thrown out at speeds between 400,000 and 2 million miles per hour.

A paper describing these results appeared in a recent issue of The Astrophysical Journal Letters and is available online (https://arxiv.org/abs/1610.01923). NASA’s Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA’s Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra’s science and flight operations.

Roughly once a year, the smallest Large Hadron Collider (LHC) experiment, LHC-forward (LHCf), is taken out of its dedicated storage on the site near the ATLAS experiment, reinstalled in the LHC tunnel, and put to use investigating high-energy cosmic rays.

Whereas ATLAS and the three other main LHC experiments – CMS, ALICE and LHCb – study all particles produced in collisions no matter in which direction they fly out, LHCf measures the debris thrown in the ‘very forward’ direction.

These forward particles carry a large amount of the collision energy, and barely change their trajectories from the direction of the initial colliding beam. This makes them ideal for understanding the development of showers of particles produced when high-energy cosmic rays strike the atmosphere.

“The idea behind the LHCf experiment is to help increase our learning about the nature of high-energy cosmic rays, by measuring and interpreting the properties of the secondary particles released when these cosmic rays collide with the Earth’s atmosphere,” explains Lorenzo Bonechi, who leads a team for the LHCf collaboration in Florence, Italy.

The experiment’s two detectors are installed 140 metres either side of the ATLAS collision point. They are not suitable to be used during normal LHC operations, and so have to wait until the machine is running with very few collisions –corresponding to a low luminosity . If the luminosity is too high, the larger number of forward, high-energy particles can heat the detector and cause permanent damage.

Image above: LHCf is the smallest of the six official LHC experiments. Each of the two detectors weighs only 40 kilograms and measures 30 cm long by 60 cm high and 10 cm wide. (Image: Lorenzo Bonechi/ CERN).

LHCf has been reinstalled near the ATLAS detector several times. This year, the experiment only installed one detector, which is taking data during this month’s heavy-ion run, where the LHC is colliding protons with lead ions. The asymmetrical nature of the collisions means one detector would be bombarded with the remnants of the lead nuclei and could be damaged.

The amount of debris which is thrown in the forward direction during collisions in the LHC and the energy carried by these particles can be compared with the predictions of hadronic interaction models – sophisticated physics models that describe collisions between protons and nuclei and the list of particles produced in these interactions.

“Over previous runs we’ve found significant discrepancies between our data and the most advanced hadronic interaction models, which are used to model how cosmic rays shower down onto the earth when they interact with our atmosphere. LHCf is trying to find evidence that could help prove which of these models provide the most reliable description. Now, scientists working in this field are making an effort to integrate our results into their models, and we might see a revolution in them in the near future,” says Bonechi.

The run with lead ions and protons began on 10 November 2016 with low intensity and low energy collisions (5.02 TeV) specifically for the ALICE detector to take measurements. But now it has ramped up to colliding the beams at 8.16 TeV, and LHCf has already collected several million particles and will continue its data taking in the coming days.

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Just five months into its two-year demonstration mission on the International Space Station, the first human-rated expandable habitat in low-Earth orbit is already returning valuable information about expandable technology performance and operations in space. Developed through a public-private partnership between NASA and Bigelow Aerospace, the Bigelow Expandable Activity Module (BEAM) launched to the station April 8, 2016, in the “trunk” of the Dragon capsule during the eighth SpaceX Commercial Resupply Service mission.

In late May, with careful instructions from the ground, NASA astronaut Jeff Williams conducted the manual expansion of the module through a series of seconds-long valve openings that allowed space station air to enter and expand BEAM. After BEAM was fully expanded with low pressure, air tanks inside the BEAM were opened with an automated controller to fully pressurize BEAM to match station pressure. From its packed to expanded configurations, the module nearly doubled in length and increased by 40 percent in diameter. This capability to increase a spacecraft’s useable internal volume after launch offers a potentially significant advantage for mission planners who seek to reduce cargo volume, maximize payload space and efficiently package structures inside a launch vehicle fairing.

Image above: The Bigelow and NASA Mission Control teams stand by as BEAM is expanded on the space station. Image Credit: NASA.

During and after expansion, sensors inside the BEAM recorded overall structural and thermal performance. Once it was confirmed that the module was maintaining pressure with no leaks during the week following deployment, Williams commenced the beginning of BEAM’s two-year demonstration when he entered the module for the first time on June 6, 2016. He entered again on June 7 and 8, outfitting the interior with additional sensors and air ventilation ducts and taking surface and air samples to test for microbes.

Steve Munday, BEAM Manager at NASA’s Johnson Space Center (JSC) in Houston, notes that the module and its sensors have performed as expected for the most part. “Through the NASA sensor suites on board, our teams on the ground, and astronaut support on station, we’re gaining extremely valuable data about the performance of expandable structures and habitats in space,” he says.

But like any advanced technology demonstration, the BEAM has offered a few surprises. “That’s why we test, to learn and explore new technology,” asserts Munday.

In fact, the successful expansion on May 28 was the second attempt. During the first attempt on May 26, the BEAM’s fabric layers expanded more slowly than was predicted by deployment models on the ground, perhaps partially due to being tightly packed for more than a year awaiting launch on SpaceX CRS-8. NASA and Bigelow Aerospace teams halted the deployment to closely compare the predictive deployment models pressure limits with actual readings to ensure that continuing expansion would pose no risk to the station or crew. On May 27, astronauts released pressure from BEAM to help the stiff fabric layers relax after the initial resistance. After reconfirming that the BEAM deployment operation posed no risk to the space station or its crew, the team restarted BEAM expansion on May 28, successfully reaching the fully expanded and pressurized configuration after about seven hours.

Thermal engineers at JSC found that BEAM was warmer than predicted, particularly in the packed configuration immediately prior to deployment. Munday suggests it could be due to less contact between the folded layers, providing more heat insulation than we expected. Warmer is better than cooler for BEAM, which has no active thermal control and relies upon air exchange with the station.

“A colder-than-expected BEAM would have increased the risk of condensation, so we were pleased when Jeff first opened the hatch and found the interior to be bone dry,” says Munday. “BEAM is the first of its kind, so we’re learning as we go and this data will improve our structural and thermal models and analyses going forward.”

Space station crew members entered the BEAM twice more in September to reinforce instruments that had loosened since installation, reboot a sensor data-relay laptop that had crashed, take additional samples for return to Earth, and perform tests inside the module to help engineers on the ground better define the structural characteristics of BEAM. NASA Astronaut Kate Rubins entered the BEAM on Sept. 5 to replace the DIDS battery packs after it was determined that drained batteries were disrupting wireless communications with the sensors. Ground operators remotely reconfigured DIDS power settings to a more efficient mode, preventing further disruptions. On Sept. 29, she entered again to conduct a series of modal tests to assess how the structure responds to impacts that cause vibrations and the structure’s ability to dampen the vibrations.

NASA and Bigelow Aerospace are pleased to report that, overall, BEAM is operating as expected and continues to produce valuable data. Structural engineers at NASA JSC confirmed that BEAM deployment loads upon the space station were very small, and continue to analyze the module’s structural data for comparison with ground tests and models. Researchers at NASA’s Langley Research Center in Hampton, Virginia, have found no evidence of large debris impacts in the DIDS data to date—good news for any spacecraft. And radiation researchers at JSC have found that the dosage due to Galactic Cosmic Rays in BEAM is similar to other space station modules, and continue to analyze local “trapped” radiation particles, particularly from the South Atlantic Anomaly, to help determine additional shielding requirements for long-duration exploration missions.

The space station is the world’s primary platform for testing and validating deep space capabilities. “The two-year BEAM mission on ISS provides us with an early opportunity to understand how expandable habitats perform in space,” says Munday. “We’re extraordinarily fortunate to have the the space station and its crew to help demonstrate and assess BEAM technology for use in future exploration missions.”

The BEAM demonstration is a public-private partnership managed by NASA’s Advanced Exploration Systems Division (AES). AES is pioneering innovative approaches and public-private partnerships to rapidly develop prototype systems, advance key capabilities, and validate operational concepts for future human missions beyond Earth orbit. Although the BEAM represents an early demonstration of deep space habitation capabilities, AES is also pursuing deep space habitation development with industry partners through contracts issued under the Next Space Technologies for Exploration Partnerships (NextSTEP) Broad Agency Announcement. Under NextSTEP, four companies (Bigelow Aerospace, Boeing, Lockheed Martin and Orbital ATK) have recently completed cislunar habitation concept studies, and all four plus Sierra Nevada Corporation, are proceeding toward contract negotiations to develop full-size ground prototypes of cislunar habitats. A sixth team led by NanoRacks was selected to complete an additional study on the repurposing of upper stages of rockets into habitats.

NASA Sets Space Fire in Second Round of Fire Safety Experiments

Fire safety is a crucial component of space living. As we partner with industry and international space agencies to develop deep space habitation capabilities, we are leveraging every opportunity to validate important habitation-related systems and operations in low-Earth orbit. The second Spacecraft Fire Safety experiment, or Saffire-II, is a fire experiment with nine material swatches that will be ignited in a cargo ship as it orbits Earth. Saffire-II is the second in a series of three fire safety experiments, and builds on the data captured during Saffire-I with an expanded test portfolio of new materials.

Cygnus Spacecraft Departs ISS (archive image). Image Credit: NASA

Saffire-II launched on OA-5 in October 2016. The nine samples in the experiment kit aboard the Cygnus cargo vehicle include a cotton-fiberglass blend, Nomex, and the same acrylic glass that is used for spacecraft windows. After the spacecraft departs the station, and before its destructive reentry to Earth, mission controllers on the ground will remotely ignite the samples.

Saffire-II mission updates will be added below as data and imagery are returned from the orbiting Cygnus vehicle.